Oxidation of alcohols



March 5, 1963 I. KIRSHENBAUM ETAL 3,080,426

OXIDATION OF ALCOHOLS Filed Jan. 29. 1959 I70 I I? l4 I I Bi I2 I I [0 H I5 I6 I 7 I l -9 I -FRACTIONATOR l i 6 8 l I I I8 I I 26 l I CATALYST REGENERATOR I I I 5 25 I I l -2s I 20 I9 I T I 3 *REACTOR lsidor Kirshenboum Emanuel M. Amir Inventors Elroy J. lncholik B.y WM Attorney 3,080,426 QXEDATEGN 6F ALCOHOLS lsidor Kirshenbaum, Westiield, N.J., Emanuel M. Amir, Bax/town, Ten, and Eiroy J. inchalik, (Iraniord, N..I., assignors, by direct and mesne assignments, to Ease Research and Engineering Company, a corporation of Deiaware Filed Jan. 2?, 1%59, Ser. No. 789,901 6 Claims. (Cl. 260-596) This invention relates to the conversion of alcohols to their corresponding carbonyl compounds in the presence of select catalytic systems. Inparticular, the invention relates to a process for the selective conversion of alcohols, preferably primary and secondary saturated acylic C to C alcohols and in particular C to C alcohols, to a predetermined carbonyl compound. Primarily, the process is designed for the production'of various aldehydes and ketones. Thus, ethyl alcohol is converted to acetaldehyde, isopropyl alcohol to acetone, secondary butyl alcohol to methyl ethyl ketone, etc. However, by controlling the extent of oxidation the corresponding acids may also be produced by this process.

-It is within the scope of this invention to employ a previously prepared alcohol feed, or, in the alternative the alcohol, or a portion thereof, may be formed in situ mm the corresponding olefins and be oxidized to the desired carbonyl compounds. It is also within the scope of this invention to use a mixed olefin-alcohol feed.

More particularly, the invention relates to a process wherein alcohols are caused to oxidize in the presence Of an acid-halogen-metal comprising catalyst mixture at temperatures in the range of 50 to 300 C. under pressures of l to 200 atmospheres, preferably at atmospheric pressure, to produce unusually high yields of the corresponding carbonyl compounds. The pH of the reaction mixture should be maintained in the range of 0.5 to 4.0 and preferably below 3.

The several embodiments of this invention hereinafter set forth represent diltcrent plan-s of operation designed to fit particular needs and to provide the producer some latitude in choosing equipment and reactants. It is, there fore, axiomatic that the embodiments herein recited are not equivalents and that while certain techniques are superior in a general sense the individual practicing the invention may find other embodiments best suited to particular facilities or sources of supply.

Although any C to C alcohol feed stock is suitable for use with most embodiments of this invention, for the embodiments utilizing olefins, preferred olefin feeds are C to C acyclic monoolefins. It diolefins are employed 7 to obtain compounds having carbonyl groups, it is preferable to employ a non-conjugated diolefin. Cyclic olefins may also be converted to carbonyl compounds by this process but the yields will be found to be somewhat lower than Where acyclic fee-d stocks are employed. When employing olefin feed stocks an organic solvent is preferably also employed.

Systems suitable for use with this invention include those comprising (1) a Group VIII metal, as elemental metal, compound or ion; (2) a halide or halogen; and (3) a source of hydrogen ions. These may be combined in a single compound such as chloroplatinic acid, H PtCl the preferred activator, or the various components may be introduced into the reaction zone as other compounds. The hydrogen ions may be obtained from acids or the desired acidity may, in some embodiments of this invenvention be obtained from Lewis type acids. The term Lewis Acid is defined in standard textbooks, e.g. Organic Chemistry by L. F. Fieser and M. Fieser, 3rd Edition (1956), Reinhold Pub. Co., New York City, New Yorlo EifiddgiZb Patented Mar. 5, 1963 Hydrogen ion sources suitable for use with this invention include HCl, H H PO trifluoracctic acid, alkyl or aryl sulfonic acids, halogen substituted alkyl or aryl sulfonic acids, etc. Lewis type acids include BR; and its complexes, e.g. BF -H O, BF -H PO etc. When a nonhalogen containing acid is employed other sources of halogens or halides such as NHgCl, MnCl CuCl etc. may be employed.

The Group VIII component of the reaction mixture may be chosen from platinium, palladium, rhodium, iron, cobalt, and nickel. It is preferred that either the platinum or palladium or both be present in the mixture. In addition, there may be present compounds or ions of Group I, II, V, VI, and VII metals, such as Cu, Ag, Hg, V, Cr, Mn, etc. There may also be present other Group VIII metal compounds or ions, e.g. Fe.

' The metal containing portion of the reaction mixture may be employed in soluble form, as a liquid slurry, as a solid; or in a combination of these forms. The metal may be introduced into the mixture in elemental form, in the form of an inorganic or organic compound such as a metal halide or metal oxide, complexes, chelates, sandwich type compounds, e.g. bis chromium benzene, or in the form of metal containing ion exchange res-ins, e.g. an ion exchange resin which has at least part of its mobile hydrogen ions replaced by the desired metal ion.

In a preferred embodiment the metal component is employed on catalyst supports such as alumina, preferably eta alumina, silica-alumina, or acid treated clays.

A preferred embodiment of this invention utilizes a metal compound, preferably a compound of platinium or palladium, on acid treated alumina or alumina containing support. The acid treating may be carried out either before or after impregnation of the support with the metal containing compound. In acid treating the material to be treated is preferably heated to about 9-00 to 1100" F. for at least 1 hour. It is then contacted with a solution containing about 7 wt. percent (based on solid) of concentrated HCl and 4 wt. percent (base on solid) of concentrated HNO in 200 Wt. percent (based on solid) of distilled water. The solid to be treated is slurried in the acid solution and then placed on a steam bath in a covered container for at least 1 hour. Temperature of the solution is about to F. The acid solution is drained off, and the catalyst is washed at least twice with 400 Wt. percent (based on solid) of distilled water. The washed catalyst is then dried at 250 F. and heated for at least 1 hour at 900 to 1100 F. The acid treated supported metal compound is an especially desirable component of the reaction mixture in the embodiment utilizing olefin feed.

Organic solvents suitable for use with the instant invention include such compounds as benzene, toluene, xylene, tetrahydro furan, biphenyl, chloro'benzene, dichlorobenzene and higher molecular weight alcohols, e.g. C to C An alcohol such as neopentyl may also be used.

The necessary mixing of reactants may be effected by conventional means such as the employment of tangential teed jets, bubbling gas through the reaction mixture, or by other conventional means such as a mechanical agitator.

The metal containing mixture requires regeneration and this regeneration may be effected either in the reaction zone or all or part of the mixture may be removed to a separate regeneration zone, treated, and recycled to the reaction zone.

The total amount of free and combined metal in the reaction zone will vary with the desired conversion, feed and the composition of the reaction mixture but should be within a range of 0.1 to 1 mole per mole of alcohol or olefin feed in the reaction zone. The organic solvent may constitute up to 90 vol. percent based on the total reaction mixture, preferably to 55 vol. percent.

Oxygen or other gases may be admitted to the reaction zone in a variety of ways. Oxygen may be passed through the zone in the form of molecular oxygen or as air or in an oxygen containing gas or liquid. In the absence of added oxygen or oxygen containing gas, at least some of the metal components of the reaction mixture must be in a higher valance state. Reaction temperatures of 50 to 170 C. are suitable when a C to C feed stock is employed but with C and higher molecular weight feed stocks especially when using olefins better results may be obtained with temperatures above 170 and up to about 235 C.

Thus, in one embodiment the alcohol is contacted in a reaction zone with chloroplatinic acid. Oxygen is passed through the agitated reaction mixture maintained at reaction temperatures. The carbonyl product is then separated by extractive washing or fractional distillation. In another embodiment, shown in Example I, the oxygen was omitted and agitation of the reaction mixture was introduced mechanically.

Example I Two moles of 95% ethanol was combined with .059 mole of H PtCl '6H O and refluxed at 80 C. for .15 minutes at atmospheric pressure. To the exit of the con denser a bubbler containing 25 cc. of ice water was attached for product recovery. After 15 minutes 2,4 dinitrophenylhydrazine was added to the bubbler solution for product identification as described by Shriner and Fuson, Identification of Organic Compounds," 3rd Edition, page 171 (1948), John Wiley and Sons, New York, New York. The 2,4 'dinitrophenyl hydrazone of acetaldehyde was thereupon precipitated. The precipitate upon combination with a 2,4 dinitrophenyl hydrazone of acetaldehyde did not depress or increase the melting point of that substance.

- Example [I One mole of 95% ethanol is contacted with 0.1 mole of H PtCl -6H O as in Example I. The yield of acetaldehyde obtained is substantially increased over the yield obtained in Example I.

In another embodiment an olefin-chlorobenzene solution is contacted in a reaction zone with an acid-halogenmetal comprising component as hereinbefore described. One reactor that may be used for these reactions is a stirred vessel of tantalum clad mild steel capable of withstanding pressures up to 3000 p.s.i.g. Air is introduced to the reaction zone at a velocity sufficient to effect turbulence. The reaction is maintained at reaction temperatures, hereinbefore set forth, until the desired conversions of the olefin to the corresponding carbonyl compound has been achieved.

Example 111 200 cubic centimeters of ethylene per minute and 1000 cubic centimeters of air were combined and bubbled through a solution of 0.059 mole of chloroplatinic acid in 500 cubic centimeters of water at 90 to 95 C. The acetaldehyde was absorbedin ice water and identified by the formation of dimethone as described in Shriner and Fuson, .Identification of Oragnic Comopunds, 3rd Edition, page 172' (1948), John Wiley and Sons, Inc., New York, New York. Dimethone is an addition product of acetaldehyde and l,1-dimethyl-3,S-diketocyclohexane. The selectivity of acetaldehyde was greater than 95%.

Dimethone: M. Pt. found, 143144 C.; Mt. Pt. in literature 144 C.

Exam'ple IV 200 cubic centimeters of ethylene per minute and 1000 cubic centimeters of air are combined and bubbled through a solution of 0.1 mole of H PtCl -6H O in 500 cubic centimeters of an equal volume mixture of chlorobenzene and water. The reaction is otherwise carried out as in Example III and a substantial increase in the yield of acetaldehyde is obtained.

In another embodiment where olefin feeds are used improved yields per pass will be obtained if the olefinic feed is diluted with the corresponding alcohol in an olefin to alcohol ratio in the range of 10:1 to 1:10, preferably 5:1 to 1:1.

In one embodiment of this invention particularly adaptable to large scale production of carbonyl compounds the olefin feed stream to a sulfuric acid-olefin hydration unit is divided allowing a portion thereof to pass through the hydration unit from whence alcohol product is recovered and mixed with the other portion of the feed stream before entering the reaction zone for conversion of the alcoholic-olefinic mixture .to carbonyl compounds. The olefin hydration processes to which this invention has applicability are those known in the art, such as the hydration of ethylene, propylene, butenes and higher unsaturates, using ,a strong acidic catalyst and those also known in the art which effect hydration in what is known as a Weak-acid alcohol process. In the former, for example, ethylene is hydrated by first absorbing it in sulfuric acid having an acid strength in the range of to wt. percent H 50 to obtain an acid extract containing about 1.0 to 1.5 moles of ethylene per mole of 100% H 50 This acid extract is then diluted to an acid strength of about 40 to 50% and hydrolyzed. The alcohol product is then stripped from the extract at a temperature in the range of to C. and a pressure in the range of 0 to 25 p.s.i. In the latter, for example, propylene may be absorbed inH SO having a strength in the range of 65 to 70 wt. percent at a temperature in the range of about 70 to 90 C. and a pressure in the range of 75 to 500 p.s.i. .to obtain an acid extract containing 0.8 to 2.0 moles of propylene per mole of 100% H 80 This acid extract is stripped of alcohol in an alcohol generation Zone. Water is usually added before stripping but due to the considerable amount of water in the dilute acid water addition can be eliminated if desired.

In another embodiment, the acid extract from the sulfuric acid hydration zone is passed directly to the reaction zone. This stream may be diluted with either water, olefins or alcohols prior to or after introduction to the reaction zone.

Example V A stream of propylene is passed into an H 50 hydration unit to form isopropyl alcohol. Part of the stream is .by-passed around the hydration unit and fed into an oxidation unit of this invention. The isopropyl alcohol is also fed to the oxidation unit. Operating the oxidation unit at 120 C. in the presence of a palladium-copperchlorine containing mixture ,slurried in a mixed Waterbenzene solvent in the presence of an alkyl sulfonic acid and a wetting agent results in a substantial conversion to acetone.

Example VI A mixed feed containing equal volumes of a C alcohol and a C olefin is contacted in a reaction zone maintained at a temperature of 200 C. and a pressure of 15 atmospheres with H PtCl which is supported on and treated with eta alumina as hereinbefore described and an organic solvent, dioxane, is added so as to comprise from 5 to 55 vol. percent of the resulting reaction mixture. Yields of the desired carbonyl product will be found to be increased over those obtained in other embodiments.

In another embodiment olefins of higher molecular weight than those of the feed stock are employed as a part of the organic solvent. This is especially applicable Where higher carbonyl compounds, especially ketones are desired as a by-product.

We have found that when carrying out the oxidation process of our invention improved yields of desired products are obtained by introducing turbulence into the reaction mixture. This may be accomplished by mechanical agitation, the use of high velocity jets for introducing reactants or other components of the reaction mixture, etc. However, one especially elfective means of increasing conversion to desired product is through the use of ultrasonic vibration.

Example VII 200 cubic centimeters of ethylene per minute and 1000 cubic centimeters of air are combined and bubbled through a solution of 0.1 mole of H PtCl -6H O in 500 cubic centimeters of water containing about 400 grams of cupric chloride. The reaction is otherwise carried out as in Example III and a substantial increase in the yield of acetaldehyde is obtained.

In another embodiment, chelating agents such as acetylacetone, iminotriacetic acid, hydroxylethyl ethylene diamine triacetic acid, di(hydroxyethyl) glycine and diethylene triamine pentaacetic acid are added to the reaction mixture. The commercially available (Dow Chemical) Versene, Versene Fe3 and Versenol may be used.

In another embodiment small amounts of activators such as HBr, O t-butyl peroxide, benzoyl peroxide, cumene hydroperoxide, or cumene when oxygen or air is present, iodine, NO, quinone, al'dehydes, isobutyro-azodinitrile, etc. are used. An especially eflicient method of operation involves the recycle of a portion of the product aldehydes or ketones. The activators may be added to the reaction zone or, where desirable, to the regeneration zone.

The reaction may be more easily understood by referring to the accompanying drawing which represents a semi-diagrammatic representation of one embodiment of the instant invention:

A mixture of butene-l and butene-2 is fed vie line 1 into reactor 2 containing a chloroplatinic acid-cupric chloride mixture supported on an acid treated eta alumina. Reactor 2 is a stirred vessel capable of withstanding pressures up to 3000 p.s.i.g. Reactor 2 is maintained at temperatures in the range of 100 to 150 C. and at pressures of 400 to 1000 p.s.i.g. A gas containing a low concentration is introduced into the reactor via line 3. A dioxane comprising solvent is introduced into reactor 2 via line 4. Butyl alcohol, aqueous butyl alcohol, or water may be introduced to reactor 2 either separately via line 5 or commixed with the butenes via line 1.

A methyl ethyl ketone, butanol, butene comprising effiuent is removed via line 6 and may be recycled directly to the reactor via valve 7 and line 8 or passed to fractionator 9 where it is separated by fractional distillation. An unreacted butene comprising overhead stream is removed via line 10 and may be purged via line 11 and valve 12 or passed via valve 13 to line 14 and recycled to reactor 2. A ketone comprising side stream is removed via line '15 and valve 16 or recycled via line 14 through valve 17 or in the alternative valve 17A may be closed and the stream recycled via 14A. An alcohol comprising fraction may be removed via line 18 and valve 19 or recycled to reactor 2 via line 20. Acids and other high boiling materials are removed via line 21. A portion of the slurried mixture in reactor 2 is removed via line 22 and passed via a separation zone not shown to regenerator 23. Regeneration is accomplished by introducing air or oxygen containing gas via line 24. Make up metal containing components, halide, (e.g. HCl) and if desired solvent are added via line 25. Activators such as ozone are introduced via line 31. Purge gases are removed from regenerator 23 via line 26 while the regenerated mixture is removed via line 27 and recycled to reactor 2. Lines and parts of the regenerator carrying acidic mixtures are lined with a petroleum resin such as an oxidized diolefin polymer, i.e. a butoxy resin.

What is claimed is:

1. An oxidation process for selectively producing aldehydes and ketones from primary and secondary alcohols, respectively, which process comprises intimately contacting in liquid phase an alcohol selected from the group consisting of primary and secondary saturated acylic C to C alcohols with chloroplatinic acid at a temperature between 50 and 300 C. and in the absence of free oxygen and recovering a carbonyl product selected from the group consisting of aldehydes and ketones.

2. The process of claim 2 wherein said alcohol is a primary alcohol and said carbonyl product is an aldehyde.

3. The process of claim 2 wherein said alcohol is a secondary alcohol and said carbonyl compound is a ketone.

4. The process of claim 2 wherein said alcohol is a C to C alcohol.

5. The process of claim 2 wherein said alcohol is contacted with from 0.1 to 1 mole of chloroplatinic acid per mole of alcohol.

6. A process for preparing acetaldehyde which comprises intimately contacting ethyl alcohol in liquid phase and in the absence of free oxygen with 0.1 to 1 mole of chloroplatinic acid permole of said alcohol at a temperature in the range of 50 to C.

References Cited in the file of this patent UNITED STATES PATENTS 1,978,824 Swallen Oct. 30, 1934 1,999,620 Van Peski et al. Apr. 30, 1935 2,010,066 Dreyfus Aug. 6, 1935 2,354,683 Hull Aug. 1, 1944 2,690,457 Hackrnann Sept. 28, 1954 FOREIGN PATENTS 713,791 Germany Nov. 14, 1941 891,209 France Nov. 29, 1943 767,409 Great Britain Feb. 6, 1957 OTHER REFERENCES Phillips: Amer. Chem. Jour., vol. 16, pages 255-77 (1894).

Chatt: Chem. Abstracts, vol. 48, page 5067 (1954). 

1. AN OXIDATION PROCESS FOR SELECTIVELY PRODUCING ALDEHYDES AND KETONES FROM PRIMARY AND SECONDARY ALCOHOLS, RESPECTIVELY, WHICH PROCESS COMPRISES INTIMATELY CONTACTING IN LIQUID PHASE AN ALCOHOL SELECTED FROM THE GROUP CONSISTING OF PRIMARY AND SECONDARY SATURATED ACYCLIC C2 TO C8 ALCOHOLS WITH CHLOROPLATINIC ACID AT A TEMPERATURE BETWEEN 50* AND 300*C. AND IN THE ABSENCE OF FREE OXYGEN AND RECOVERING A CARBONYL PRODUCT SELECTED FROM THE GROUP CONSISTING OF ALDEHYDES AND KETONES. 